Field of the Invention
The present invention relates to the field of photographic film assemblages of the type including a container holding a plurality of film units, and more particularly to a light sealing arrangement for a withdrawal slot at one end of the container through which a film unit is adapted to be extracted therefrom.
Description of the Prior Art
The present invention relates to an improvement in a film assemblage of the general type disclosed in the U.S. Pat. No. 3,587,426, granted to Irving Erlichman on June 28, 1971. The assemblage comprises a film container, including a forward wall having a light-transmitting section or exposure aperture therein and an end wall cooperating with one end of the forward wall to define a withdrawal slot therebetween at one end of the container, in combination with a plurality of film units arranged within the container in stacked relation behind the forward wall with their photosensitive surfaces facing the exposure aperture. The forwardmost film unit in the stack is positioned adjacent the interior surface of the forward wall in alignment with the withdrawal slot at the end of the container. Such film assemblages are especially well suited for use in self-developing cameras of the type adapted to support the film container in position to locate the forwardmost film unit at an exposure plane within the camera and thereafter sequentially expose and advance the film units through the withdrawal slot into engagement with a processing assembly located adjacent thereto.
The above-mentioned patent sets forth a light sealing arrangement for the withdrawal slot which consists of a sheet of flexible, resilient, opaque material disposed within the container between the end of the stack of film units and the end wall. The sheet is dimensioned such that it extends past the withdrawal slot in closing relation thereto and abuts the interior surface of the forward wall. As the forwardmost film unit is advanced through the withdrawal slot, it deflects the top end of the sheet abutting the forward wall to unblock the slot. Once the film unit has been extracted from the container, the inherent resiliency of the sheet material causes it to return to its blocking or light sealing position.
While this light sealing arrangement functions in a satisfactory manner once the container is located within the camera, it may be deficient in its ability to protect the film units from actinic light prior to and during insertion of the container into the camera.
The container is formed of a thin-gauged material, preferably a plastic such as polystyrene. As the user handles the container, it is possible that he will squeeze its side walls which depend from the forward wall and cause the end of the forward wall defining the withdrawal slot to bend or bow creating a space between the interior surface of the forward wall and the top edge of the opaque sheet thereby destroying the integrity of the light seal. Also, it is probable that the user will push on the end wall of the container during its insertion into the camera and possibly deflect the light seal from its blocking position.
Another problem associated with this particular light sealing arrangement is economic in nature. While the opaque light sealing sheet is quite inexpensive, the manufacturing cost associated with accurately positioning the sheet within the container is appreciable. If a space is left between the interior surface of the forward wall and the top edge of the sheet, the seal is ineffective. On the other hand, if the sheet is positioned too close to the forward wall, the top end may possibly bend around the forwardmost film unit and interfere with its being extracted from the container.
Therefore, it is desirable to provide a film assemblage of the type described with a light sealing arrangement for the withdrawal slot which is inexpensive to manufacture and is of such a construction that the seal will maintain its integrity while the film container is being handled by the user.